1. Field of the Invention
The present invention relates to a radio phone equipment, and more particularly to a radio phone apparatus for credit card for making a telephone call by the use of a credit card or a charge card.
2. Description of the Related Art
Progress of mobile phone services in recent years demands a mobile phone with which passengers taking an omnibus, a sightseeing bus, and a taxi, etc., can freely give a telephone call. Prior techniques in such a field are known in for example "Design of Car Equipment for Mobile Public Phone" issued by Electric & Communication Laboratory of NTT, vol. 33, No. 4 1984, p.p. 771 to 783 (1984) or in "Versatile Services of Mobile Phone" Telecommunication Facilities, vol. 36, No. 8, p.p. 115 to 118 (1984) in NTT Facility Division.
A mobile phone described in these references is that of coin dispensing public type wherein the charges for telephone calls are selectively collected without fail without troubling a carman when the phone is employed by passengers taking an omnibus, a sight-seeing bus, and a taxi, etc.
However, such a coin dispensing system suffers from the following problems:
(a) A user must have a proper amount of coins with him.
(b) Processing for charging as a coin type mobile phone is needed to result in a complicated circuit therefor as well as deteriorated speech quality. Moreover, a strong box to house coins is needed. Thus, the mobile is heavy-weighted and is costly.
(c) Usage of the mobile phone must be limited depending on a capacity of the strong box when the box is full with coins and hence coins must be withdrawn periodically.